[FAQ] 工具同步过程报错 unsupported modify

🌌 运维指南 TiDB 常见 FAQ
1

[问题澄清]

DM同步过程中遇到报错：unsupported modify charset from binary to utf8mb4

[原因分析]

修改int为varchar类型时报错

mysql> alter table test10 change column a a varchar(20);

ERROR 1105 (HY000): unsupported modify charset from binary to utf8mb4

tidb不支持变更列修改

[解决方案]

建立列为varchar的表，导入数据，保证数据一致，删掉原本，rename varchar表.

[参考案例]

[引申学习点]

升级后常见问题

https://pingcap.com/docs-cn/stable/faq/upgrade/#%25E6%2589%25A7%25E8%25A1%258C-ddl-%25E6%2593%258D%25E4%25BD%259C%25E6%2597%25B6%25E9%2581%2587%25E5%2588%25B0%25E7%259A%2584%25E5%25AD%2597%25E7%25AC%25A6%25E9%259B%2586-charset-%25E9%2597%25AE%25E9%25A2%2598